Receivables from and Payables to Broker-dealers, Clearing Organizations and Customers - Schedule of Receivables from and Payables to Broker-dealers, Clearing Organizations and Customers (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Receivables from broker-dealers, clearing organizations and customers:
Securities failed-to-deliver - broker-dealers and clearing organizations	$ 135,313	$ 282,125
Securities failed-to-deliver - customers	333,048	284,322
Cash deposits with clearing organizations and broker-dealers	93,754	115,151
Other	15,877	6,338
Total	577,992	687,936
Payables to broker-dealers, clearing organizations and customers:
Securities failed-to-receive - broker-dealers and clearing organizations	226,163	125,022
Securities failed-to-receive - customers	157,822	405,186
Other	8,861	7,190
Total	$ 392,846	$ 537,398